Have 2017 V still under warranty. Twice in last month had dead battery, no start. towed twice to dealer. charged battery said could not find any problem. Told them something obviously drawing on battery or battery is bad. Said needs to be driven to keep battery charged. Said no way should battery go dead sitting less than week. One service guy said they have had problems like this but offered no remedy except to call Toyota customer service. Anyone have any information to help meow here. Dave
Obviously a good battery load check is the first step. I would take the battery to an auto supply or independent mechanic for that test. Then you might check the back hatch light. If the hatch is not 100% closed everytime, the hatch light can kill the 12v. It happened to me a few times since its a low amp hour battery. The other interior lights will time out but not the hatch. It can be turned off With the adjacent switch and or replaced with an equivalent led. Other than that you need to have the off current draw measured after a few minutes when all of the ecus go into a powerdown. It should draw less than 50 ma (0.050 amps) with auto headlights enabled or > 40 ma with auto lights disabled. It will read much higher immediately after shutdown. 50 ma should be low enough for a month and still start (go to ready).
